/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

Description

\*---------------------------------------------------------------------------*/

#include <unistd.h>

#include "error.H"
#include "timer.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
defineTypeNameAndDebug(timer, 0);

jmp_buf timer::envAlarm;

struct sigaction timer::oldAction_;

unsigned int timer::oldTimeOut_ = 0;
}


// * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //

void Foam::timer::signalHandler(int)
{
	if (debug)
	{
		Info<< "Foam::timer::signalHandler(int sig) : "
			<< " timed out. Jumping."
			<< endl;
	}
	longjmp(envAlarm, 1);
}

// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::timer::timer(const unsigned int newTimeOut)
:
	newTimeOut_(newTimeOut)
{

	if (newTimeOut > 0)
	{
		// Is singleton since handler is static function
		if (oldTimeOut_ != 0)
		{
			FatalErrorIn
			(
				"Foam::timer::timer(const unsigned int)"
			)   << "timer already used."
				<< abort(FatalError);
		}

		// Install alarm signal handler:
		// - do not block any signals while in it
		// - clear list of signals to mask
		struct sigaction newAction;
		newAction.sa_handler = timer::signalHandler;
		newAction.sa_flags = SA_NODEFER;
		sigemptyset(&newAction.sa_mask);

		if (sigaction(SIGALRM, &newAction, &oldAction_) < 0)
		{
			FatalErrorIn
			(
				"Foam::timer::timer(const unsigned int)"
			)   << "sigaction(SIGALRM) error"
				<< abort(FatalError);
		}

		oldTimeOut_ = ::alarm(newTimeOut);

		if (debug)
		{
			Info<< "Foam::timer::timer(const unsigned int) : "
				<< " installing timeout " << int(newTimeOut_)
				<< " seconds"
				<< " (overriding old timeout " << int(oldTimeOut_)
				<< ")." << endl;
		}
	}
}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

Foam::timer::~timer()
{
	if (newTimeOut_ > 0)
	{
		if (debug)
		{
			Info<< "Foam::timer::~timer(const unsigned int) : timeOut="
				<< int(newTimeOut_)
				<< " : resetting timeOut to " << int(oldTimeOut_) << endl;
		}

		// Reset timer
		::alarm(oldTimeOut_);
		oldTimeOut_ = 0;

		// Restore signal handler
		if (sigaction(SIGALRM, &oldAction_, nullptr) < 0)
		{
			FatalErrorIn
			(
				"Foam::timer::~timer(const struct sigaction&"
				"const struct sigaction&)"
			)   << "sigaction(SIGALRM) error"
				<< abort(FatalError);
		}
	}
}

// ************************************************************************* //
